In a discussion that wandered into asteroid mining possibilities I wondered what is known with confidence about the mineral resources within asteroids. Reconciling the estimates thrown around with the admitted large uncertainty about the quality of mineral ores within asteroids seems to be essential to estimating the economic viability of any attempts to exploit them. Clarity about what form the desired materials take rather than simple estimates of concentrations and total quantities is needed; a pure elemental metal, even at low concentrations may have good potential for mining - relatively simple techniques can separate and concentrate them - whereas higher concentrations but in the form of alloys with other metals are not so desirable. Not impossible to separate and purify but involving far more complex and costlhy. Examining meteorites here on Earth appears to be the primary source of estimates of mineral potential.

The presence of nickel-iron as kamecite and taenite is certain, but is there evidence of the presence of relatively pure iron that is not alloyed with nickel? Whilst there is an existing market for alloys of nickel and iron, if it is pure iron or nickel that is wanted, separating them is no easy matter.